(原創) derived-class要怎麼呼叫base-class的constructor? (.NET) (C#)
Abstract
有時我們在derived-class的constructor提供的參數,事實上是base-class的資料,或者base-class根本就是ABC(abstract base class),這時我們就得在derived-class的constructor去呼叫base-class的constructor。
Introduction
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/*
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(C) OOMusou 2007 http://oomusou.cnblogs.com
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Filename : Constructor_CallBaseConstructor.cs
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Compiler : Visual Studio 2005 / C# 2.0
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Description : Demo how to call base class constructor
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Release : 02/16/2007 1.0
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*/
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using System;
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namespace CSharpLab
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{
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class Student {
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public string name;
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public Student(string name) {
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this.name = name;
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}
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}
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class Bachelor : Student {
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public string lab;
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public Bachelor(string name, string lab) : base(name) {
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this.lab = lab;
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}
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public static void Main() {
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Bachelor bachelor = new Bachelor("John", "PECLab");
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Console.WriteLine(bachelor.name);
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Console.WriteLine(bachelor.lab);
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}
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}
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}

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執行結果


24行的constructor提供了兩個參數,name為base-class的資料,而lab為derived-class的資料,所以勢必呼叫base-class的constructor才行,C#的方式是在constructor initializer list使用base keyword,並帶入參數,這樣就可以執行base-class的constructor了。
C++是在constructor initializer list呼叫base-class的constructor,而Java是在body中使用super這個keyword。
See Also
(原創) derived-class要怎麼呼叫base-class的constructor? (C/C++)
(原創) derived-class要怎麼呼叫base-class的constructor?(Java)